The GOP nomination assured, Romney marched this week through three states vital to both men.
In North Carolina, which Obama narrowly won in 2008 but where Republicans see an opening this year, Romney taunted the president with a slashing attack delivered across from the Charlotte stadium where Obama will give his Democratic convention acceptance speech in September.
The trip mirrored 2008. That year, after dispatching primary rival Hillary Rodham Clinton, Obama went to St. Paul, Minn., for a victory speech that helped him pivot toward John McCain. It was no coincidence that he spoke in the same hall where Republicans would later formally nominate McCain.
Obama visits North Carolina early next week. As Romney spoke there this week, Obama was campaigning in Ohio — his fourth visit since January. He carried the state in 2008 but faces a harder time now.
Sure enough, Romney showed up in Ohio the next day, asserting at a shuttered factory that Obama's policies have slowed recovery and kept the plant from reopening. No Republican has ever won the White House without carrying Ohio.
Romney was wrapping up Friday in Arizona. McCain won his home state last time, and it usually votes Republican. But it could be more competitive now because of a rising Hispanic population. Obama holds a big edge in national polls over Romney among Hispanic voters.
Team Obama is plowing resources into Arizona. Campaigning Thursday in Phoenix, Vice President Joe Biden claimed "a real shot" at a win.
The campaign shadowing may only increase as the election season ripens and schedules become more poll-driven.
For now, it's sometimes hard to tell which candidate is the cat and which the mouse.